Method of making mufflers and the like



2 Sheets-Sheet 1 Jam.23,l945. c.M.BUcK

METHOD OF MAKING MUFFLERS AND THE LIKE Filed April 29, 1940 @43 @Wm Vl Jam, 23, i945. c. M. BUCK METHOD OF MAKING MUFFLERS AND THE LIKE Filed April 29. 1940 2 Sheets-Sheet 2 Patent-esi Jan. 23, w45

METHOD @F Clarence M. Buck, `laclxson, Mich., assiznor to Hayes Industries, Inc., Jackson, Mich., a corporation of Michigan Application April 29, 1940. Serial No. 332,173 2 claims. (ci. ess- 157) The present invention relates to muiiiers and to a method of making the same and particularly to a muiiier produced by the apparatus disclosed in my co-pending application Serial No. 332,174 filed April 29, 1940.

Before the employment of outwardly projecting louvers on muiiler tubes, it was the practice to provide baiiles having central openings through which the mulller tube was disposed and then to spot weld the bailles onto the tubes to secure them in position. However, since the employment of vlouvers having projecting portions came into use, it was necessary to make the opening in the louvers of such size as to clear the louvers. Since the openings in the bailles were of such size as to prevent a snug t on the portion of the tube not provided with louvers, it was then necessary to crimp the bames in order to bring the central opening down to a size whereby the bales could be secured to the tube by some convenient method such as spot welding. The crimping operation is unsatisfactory as such and is expensive. Particularly unsatisfactory is the misalignment of the baiiles that results in making diiiicult subsequent telescoping over the baiies of an outer shell or tube. Another prac tice has been to roll ridges in sheet metal before rolling it into muiiler tubes and then mounting bales on the ridges on the tubes. An example of this practice is disclosed in Patent No. 1,878,424 to Oldberg. This method is unsatisfactory because in lock seeming the muiiler tubes, the ridges are crushed. According to the present invention, the tube has limited lengths thereof expanded into peripheral contact with enlarged openings in the baiiles. As an additional renement, a bead is struck up from the expanded portions of the tube on each side of the balles to prevent axial movement of the bailles with respect to the tube. With the bales thus assembled on a, tube, an alignment of the baiiles is obtained which makes the telescoping of an outer shell or tube onto the baiiles a simple matter and a muiler section isobtained wherein there is a degree of peripheral engagement between the bailles and the inner and outer tubes not possible when employing prior assembling practices.

An object of the invention is to provide a mulder having a tube provided ywith an external annular ridge supporting thereon a baille.

Another object of the invention is to provide a muiller having a tube provided with an exteron and a bead at each side of the baille for preventing axial movement of the baille with respect to their tubes.

A further object of the invention is to provide a mudier having a baiile between inner and outer tubes provided by an outwardly expanded portion in the inner tube and an inwardly directed portion in the outer tube, the two portions being in peripheral engagement.

A still further object of the invention is to provide a method for securing baiiles to tubes in mulliers or the like which comprises outwardly expanding an annular ridge from the material of the tube into engagement with a baille disposed in a desired relation on the tube.

A still further object of the invention is to provide a method of securing a bailie to a tube which comprises expanding outwardly an annula ridge from the material of the tube into engagement with a baffle in the desired relation on the tube and expanding from the expanded portion a bead on each side of the baille to prevent axial movement thereof with respect to the tube.

A still further object of the invention is to provide a bale between an inner and an outer tube in a mutller by forming in the outer tube an annular ring inwardly of the surface of the tube, disposing an inner tube within the outer tube and radially expanding an annularring from the material of the inner tube into pe ripheral engagement with the inwardly extending ring of the outer tube.

A still further object of the invention is to provide -a mumer tube and the method of mak ing the same wherein there is an integral, uncrushed ridge including a lock seam.

These and other objects will be apparent from the following specification when taken with the accompanying drawings, in which:

Fig. 1 is a vertical section of a muiller disclosing the present invention,

Fig. 2 is section on the line II-II of Fig. 1,

Fig. 3 is a vertical section of a portion of a muiiler disclosing the invention,

Fig.. 4 is a vertical section of apparatus for.

expanding a tube onto a baille according to the present invention,

Fig. 5 is a partial section taken through a muiiler tube and ridge forming apparatus at the apex of the ridge, showing the arrangement for nal annular ridge with a baille supported there'- 55 providing a smooth external periphery for the ridge notwithstanding the lock seam in the tube.'

Fig. 6 is a vertical section of another muiller, and

. the baille 8 onto the tube I.

Pig. 'I is a partial section showing on enlarged scale a bame attached to a tube.

Referring particularly to the drawings. there is disclosed in Fig. 1 a muiiier according to the present invention. The muiiler consists of a through inner tube I. a tube 2 surrounding the through tube I, and an outer shell 8. The ends of the munier are provided with heads 4 which do not form a part of the present invention. A banie 8 forms a' partition between the through tube I and the tube 2. The through tube I is provided with a plurality of louvers 8 which are provided with portions projecting outwardly from the tube l and as shown particularly in the drawings. Because of these outward projections, it is necessary that the opening in the balde 8 through which the tube I is projected be of a larger diameter than the diameter of the tube itself in order to clear the projections of the louvers 8. The previous practice was to crimp However, according to the present invention, the inner tube I fhas a limited length thereof beneath the baille 5 expanded into a ridge 1 into peripheral engagement with the baie 8.

Referring to the drawings. it will be observed that the baille 5 is provided at the portion in contact with the ridge 'I with an axially extending flange 8. At each side of the flange 8 is an expanded bead 8, annular in configuration and retaining the baille 8 against axial movement with respect to the tube I. The tube I and the flange 8 may be spot welded together or not as desired.

In Fig. 2 is shown another application of the invention wherein a through tube I8 provided with louvers I6 has associated with it an outer tube I1. In the portion of the through tube I8 disclosed are three radially expanded ridges I8 corresponding to the ridge 1 of Fig. 1. The ridges I8 are expanded from the metal of the tube I5 intov peripheral engagement with the flanges I9 of bailles 28 and the ballles 28 are held against axial movement with respect to the tube I5 by integral expanded beads 2| at each side of the flanges I8. When the bales 28 have been secured to the tube I5, the outer tube I1 is telescoped onto the bai'iles 28 and secured thereto in some suitable manner as by spot welding.

-Another form of the invention is disclosed in Figs. 1 and 3 wherein a baille is formed from the material of the tubes I and 2. The tube 2 has a portion thereof necked down to provide an annular ring 25 of considerably less diameter than the diameter of the tube 2. In Fig. 3 is shown more particularly the way in which the tube 2 is necked down. The excess material of the tube 2 over that which is included in the ring 25 is utilized in folds 26. The necking down of the tube 2 may be accomplished in a manner specifically disclosed 'in the co-pending application of Beecher B. Cary, serial No. 221,474, flied July 27, 1938.

In the portion of the tube I directly opposite the ring 25 there is expanded an annular ridge 21 similar to the ridge 1, with the exception that it is not provided with the annular beads 8. The ridge 21 is expanded into peripheral engagement with the ring 25 so as to form with the portion of the tube 2 necked down to form the ring 25, a baille providing with the ybaille 5 and the tubes I and 2 a high frequency resonance chamber 28.

The apparatus for expanding the ridges in the inner tube to support a surrounding bale is dis closed particularly in my copending application, executed on even date herewith. The apparatus co-pending application, the members 82 are in the form of two halves permitting Opening of the halves for placing the bames 88 and for removing the tube 8| having the bailies 88 secured thereto. In the use of the structure disclosed in Fig. 4, the

-halves of the clamping members 82 are separated to permit placement of bellies 88. The tube 8| is then disposed through the openings in the bailles 88 and the halves of the clamping members 82 brought together to lock the baiiles 88 in a predetermined relation with respect to the tube 8|. As shown in the drawings, the clamping members 82 when in. assembled relation with the tube 8| limit the length of the ridges which are to be ex panded. When the clamping members 82 have been clamped as aforesaid, a quill 38 is disposed in the tube 8|, the quill 88 being provided internally with a mandrel 34 having therein camming surfaces 88 for engaging with follower members 88 which comprise portions of radially movable segmental dies 81. It will be understood that there are a plurality of dies 81 circumferentially arranged around those portions of the quill 88 at which ridges are to be expanded. The follower portions 88 of the dies.81 project inwardly through openings 38 in the quill 88. The dies 81 as well as the quill and mandrel structure and the structure for actuating the same are more particularly disclosed in my aforesaid co-pending application.

While the quill 88 is maintained stationary, the mandrel 84 is drawn longitudinally (to the left in Fig 4) with respect to the quill 88 to cause the camming surfaces 88 to cam the dies 81 radially outwardly into engagement with the tube 8| to form annular ridges 88. Backing up rings 48 are provided for the flanges 4| of the ballles 88. The rings 48 are supported with respect to and move with the clamping members 82 and like the clamping members 82 are in two halves. The internal diameter of the vbacking up rings 48 should be slightly greater than the finished external diameter of the flanges 4I for the reason that as the dies 31 radially expand the ridges 88 and then withdraw, the resiliency of the metal of the tube 8| will result in a ilnal diameter of the ridges 39 which is slightly less than the maximum diameter during the expanding, and unless the diameter of the rings 48 is as stated, a good peripheral engagement of the ridges 89 with the flanges 4I will not be obtained. Each of the dies 81 is acted upon by a cantilever leaf spring 42, each of which moves a die 81 radially inwardly when the mandrel 84 is moved inwardly with respect to the quill 88 after the expanding operation has been completed. It will be observed that the dies 81 are provided with beads 48 for providing corresponding beads 44 in the ridges 88 for the purpose of supporting the baille 88 against axial movement with respect to the tube 8| as has been hereinabove explained with respect to 'the structures disclosed in Figs. l and 2.

An important function of the clamping members 82, together with the backing up rings 48 is to support the banles 88 in a predetermined alignment so that the ballles when they are secured to the tube passing through them may be readily telescopically assembled in an outer tube. While in the form of the invention clisclosed, the axial augment of the baliles 30 is controlled by the flanges 4| thereof, abutting against the backing up rings 40, it will be appreciated that the bailles 3 themselves may be accurately. formed to close limits and therefore the outer peripheries thereof will be in true axial alignment when the anges 4| are maintained in true axial alignment. This alignment results in simplifying the telescoping of an outer tube over bafiies and provides a muilier section having an accurate peripheral engagement between the battles and tube surrounding them.

While in Fig. 1, there have been disclosed beads 9, raised from the ridges 1 for preventing axial movement of the bailles 5 with respect to the tube I, it will be appreciated that in the place of the ridges 9, there may be provided a series of radially extending, circumferentiallyspaced, disconnected projections without departing from the spirit and scope of the invention. Furthermore, it will be appreciated that while the bailles have been disclosed as havingcentral openings, the openings through the bailles may be off-center. A case where the openings to baiies would be olf-center is where the baliles are elliptically shaped, for instance where a retroverted ow type of tube is employed.

One feature of the present invention which is not readily obvious is the fact that the point at which the baiiies are secured to the through tube remains cooler during operation than other portions of the through tube. The reason for this apparently is because the ridges supporting the baille provide, with respect to the interior of the through tube, a channel past which the ex# haust gases from the internal combustion engine with which the muilier is used flow. As the gases flow by these channels they draw a vacuum of some unknown degree in the channels which results in insulating the outer sides of the ridges from the hot gases. Also the outer sides of the ridges to which the baflies are connected are out of the main paths of the hot exhaust gases. It is believed that it is the combination of these two factors which results in the outer sides of the bale supporting ridges remaining cooler than the rest of the inner tube in which the ridges are formed. As a result the life of these portions of the inner tube is prolonged and since it is the points of connection of bailies to the inner tube which fails first in service, the life of the muilier is considerably prolonged.

As pointed out hereinabove, one of the diiliculties encountered in rolling baille supporting ridges in sheet metal before it has been formed into tubes, resides in the fact that in lock seaming the edges of the metal in forming the tubes, the ridges are crushed. The present invention not only overcomes this dimculty but also provides a smooth and continuous surface at the periphery of each ridge by disposing the lock seam inwardly of the surface of each ridge. A section of a muiller tube and the arrangement for dispositing the lock seam inwardly of the peripheral surface of a ridge is disclosed in Fig. 5. As shown, the tube 3| is supported on the quill 33 surrounding the mandrel 34 and dies 31, have been cammed radially, through the followers 36, to expand a portion of the tube 3| into a ridge 39, against a backing ring 40. According to the invention, one of the dies 3l is provided with an axially extending recess 50 for receiving the lock seam 5i in the tube 3|. Prior to forming the ridge 39 when the tube 3| is assembled with respect to the quill 33, the recess 60 is disposed opposite the lock seam 5|. It will be understood that prior to the radial movement of the die 31 to expand the ridge 39, the lock seam 5| will be at least in part raised above the exterior surface of the tube 3|, as is usual from ordinary lockseaming operations in the formation of lock seamed tubes from sheet metal. When the dies 3'| are moved outwardly, the lock seam 5|, as the result of the resisting action exerted by the backing ring 40 is moved into the axial-recess 60 and the ridge 39 is provided with a continuous smooth exterior surface. Thus there is provided a tube having an integral ridge which is not crushed at the. lock seam and the leakage which occurred between the baille and the crushed ridge of the prior practice is eliminated.

Another use to which the invention may be put is disclosed in Fig. 6. A muffler through tube 60 is provided with a plurality of bailles 6|, secured thereto according to the present invention. The through tube 60 is also provided with a plurality ofbaies 62, also secured according to the present invention. It will be observed that the external diameter of the bailles 6I is substantially less than that of the bailles 62 and that an intermediate tube 63 is telescoped over the bailies 6I and an outer shell 64 is telescoped over the bailles 62. Thus, While in the form of the invention disclosed in Fig. 2, the bailles 20 were of uniform size to permit the alignment thereof for telescopically receiving a tube, the baflles in y Fig. 6 are of different sizes but nevertheless are aligned in groups according to sizes to permit the telescoping thereover of tubes of different diameters according to a predetermined muiiler design.

It will be observed that the baffles 6| and one of the baiiles 62 are supported on the ridges 65, corresponding to the ridges I8 disclosed in Fig. 2, and that the other baffle 62 is not supported on a ridge, but is maintained against longitudinal displacement by expanded beads 66 corresponding to the beads 2| disclosed in Fig. 2.

It will be appreciated that while the invention has been illustrated as applied to the securing of baliies to tubes wherein the portions of the tube to which the bailies are secured are of less effective diameter than the extreme diameter of portions of the tube having outwardly projecting louver portions over which the bales must passy in assembling, the invention is equally applicable to constructions wherein the tube has no externally projecting louvers and therefore no substantial baille supporting ridges are required. In other words, the feature of the invention which provides an exact axial alignment of the baiiles to permit them to be assembled telescopically in an outer tube after being secured to an inner tube may be used with or without the baille supporting ridge expanded from the inner tube. The right baille 62 in Fig. 6 illustrates the manner of securing a. baille where there are no louvers over which a baille must' be passed in assembling, that is, the case where it is not necessary to radially expand ridges of substantial height to support the bales, but where the tube supporting the bailies is expanded only suiiiciently to clamp the bailles. It will be observed that as shown in Fig. 6, the end portion 61 of the through tube 60 is not provided with outwardly projecting louvers and therefore the end baille 62 may be readily slipped over the end portion 6l, even though the diameter of the opening in the end baille 62 is only very slightly greater than that of the end portion 61. It will be understood that the beads Il, disclosed in Fig. 6, are expanded in the tube lli in the same manner as the beads 2| disclosed in Fig. 2 are formed.

Another advantage of assembling bailles on tubes, according to the present invention, is that in the event that a tube upon which a baiile is to be assembled is slightly out of straight alignment, the ridge for supporting the baille may be formed so as to be concentric with the desired position of the outer periphery of the bame, notwithstanding the fact that it may not be concentric with the tube in which it is formed. This feature of the invention is illustrated in Fig. 7, wherein a tube 10 is provided with a ridge 1i, not concentric with the tube 10 and supporting a baille 12. The eccentrlcity of the ridge 1| is disclosed by comparing the dimensions x and u, the dimension :c being smaller than the dimension y. 'It will be clear that the eccentricity of the ridge Il is due to the fact that the quill and mandrel supporting the expanding dies for forming the ridge ll is sufilciently rigid to make the ridge 1| concentric with it, notwithstanding any eccentricity of the tube 'l0 with respect to the quill and mandrel. The eccentric ridge 10 may be produced either when a, substantial ridge, such as the ridge 6i, disclosed in Fig. 6, is produced, or when a negligible ridge, such as that disclosed in association with the beads 8G of Fig. 6, is produced. In either case the bailles secured will be in alignment to enable telescopic reception of an outer tube notwithstanding any irregularity or the inner tube to which the bailies are secured.

Having thus described my invention, what I desire to secure by Letters Patent and claim is: 1. The method of providing a baille between an inner and an outer tube oi substantially dinerent 'diameters which comprises crimping the outer tube to provide an inwardly extending annular ring of less diameter than the tube, disposing said inner tube in said outer tube, and expanding a portion or the inner tube oppositesaid inwardly extending annular ring into peripheral engagement therewith by subjecting said tube portion to a radially outwardly expanding force, whereby said inwardly and outwardly extending tube portions comprise a baille between said tubes.

2. In the manufacture oi' muiers, the method of providing a baille between an inner and an outer tube of substantially din'erent diameters which comprises providing an outer tube having a portion thereof of less diameter than the tube itself, disposing the inner tube within the outer tube, and expanding a portion ot the inner tube into peripheral engagement with said portion of said outer tube by subjecting said tube portion to a radially outwardly expanding force, whereby said inwardly and outwardly extending tube portions comprise a baille between said tubes.

CLARENCE M. BUCK. 

